Abstract: The existing thinning algorithms have many problems, such as pixel redundancy, bifurcation and distortion. In order to solve these problems, first of all, on the basis of ZS（ZHANG and SUEN） parallel thinning algorithm, two corresponding sub-processes are increased in ZS（ZHANG and SUEN） algorithm, so that skeleton image closer to centerline is gotten; then, by increasing judgment conditions and designing remove templates, an improved EPTA parallel thinning algorithm is proposed. Improved EPTA algorithm can solve pixel redundancy, 2-pixel slash thinning distortion limitation of EPTA. Experiment results show that the improved EPTA thinning algorithm can get more accurate 1-pixel results.

Key words: thinning, ZS parallel thinning algorithm（fast parallel thinning algorithm）, Enhanced Parallel Thinning Algorithm（EPTA）, eliminate template, binary image

摘要： 为了解决现有细化算法中像素冗余、分叉、畸变等问题，在ZS（ZHANG和SUEN）并行细化算法的基础上增加了两个映像子过程，获得了更加接近中心线的骨架图像；通过增加判决条件并设计消除模板，提出了一种改进的EPTA并行细化算法，解决了EPTA细化算法的像素冗余、二像素宽度斜线细化局限性畸变等问题。实验结果表明改进的EPTA细化算法能得到更准确的完全细化结果。

关键词: 细化, ZS并行细化算法（快速并行细化算法）, 增强并行细化算法, 消除模板, 二值图像